Papers by Evgeni Chesnokov
Geophysical Journal of the Royal Astronomical Society, Nov 1, 1986
Distributions of microcracks in a rock mass will tend to become aligned in the presence of a devi... more Distributions of microcracks in a rock mass will tend to become aligned in the presence of a deviatoric stress-field, and the aligned distribution will be effectively anisotropic to the propagation of seismic waves. The diagnosis and analysis of crack-induced anisotropy is important, since it will give information on the crack geometry and in situ stress field, and cracks and stress are important whenever we penetrate the surface of the Earth. Analysis of three-component shear-wave records for evidence of shear-wave splitting offers the best method for the detection and evaluation of crack-induced anisotropy. The most common stress distribution in the crust results in distributions of vertical, parallel cracks. Previous theoretical studies have shown that the horizontal projection of the polarization of the faster split shear-wave through a system of near-vertical, parallel cracks is aligned parallel to the strike of the cracks for propagation within most of the shear-wave window at the surface. Dry and saturated crack-systems produce different patterns of polarizations, and the patterns also depend on the degree of tilt of the cracks. A comparison of observed and theoretical polarization projections is made, using a large suite of three-component shear-wave data from local earthquakes. The horizontal polarizations demonstrate the existence of a system of near-vertical parallel cracks in a preferred azimuthal alignment. However, when coverage of the shear-wave window is incomplete, they do not permit a precise determination of the inclination of the cracks, or even the degree of saturation. This paper examines, for the first time, the polarizations of the split shear-waves in vertical projections. The projection patterns in the vertical-transverse plane are fundamentally less easy to recognise, and are not likely to give more information on the inclination of near-vertical cracks than that which can be derived from analysis of the horizontal polarization projections.
Seg Technical Program Expanded Abstracts, 2007
SEG Technical Program Expanded Abstracts 2007, 2007
A technique allowing the determination of 3D distribution of both compressional and shear wave ve... more A technique allowing the determination of 3D distribution of both compressional and shear wave velocities in shales from limited number of experimental data has been developed. The technique involves an EMT (effective medium theory)‐based inversion of shale's ...
SEG Technical Program Expanded Abstracts 2009, 2009
2011 International Conference on Infrared, Millimeter, and Terahertz Waves, 2011
The Novosibirsk FEL (NovoFEL) generates tunable monochromatic coherent radiation as a continuous ... more The Novosibirsk FEL (NovoFEL) generates tunable monochromatic coherent radiation as a continuous stream of 100-ps pulses with a repetition rate of up to 11.2 MHz and average power of up to 500 W. After commissioning of the second laser resonator in 2010, the spectral ranges of 120–240 μm and 40–80 μm are available to users. A review of experimental results
2007 Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics, 2007
Progress in the construction of the second stage of Novosibirsk free electron laser and main resu... more Progress in the construction of the second stage of Novosibirsk free electron laser and main results obtained during the year at the terahertz user stations are described.
2009 34th International Conference on Infrared, Millimeter, and Terahertz Waves, 2009
High power THz applications on the Novosibirsk terahertz free electron laser are described.
SEG Technical Program Expanded Abstracts 2014, 2014
Proceedings of the Combustion Institute, 2005
Several elementary reactions of formyl radical of combustion importance were studied using pulsed... more Several elementary reactions of formyl radical of combustion importance were studied using pulsed laser photolysis coupled to transient UV-Vis absorption spectroscopy: HCO fi H + CO (1), HCO + HCO fi products (2), and HCO + CH 3 fi products (3). One-pass UV absorption, multi-pass UV absorption as well as cavity ring-down spectroscopy in the red spectral region were used to monitor temporal profiles of HCO radical. Reaction (1) was studied over the buffer gas (He) pressure range 0.8-100 bar and the temperature range 498-769 K. Reactions and as well as the UV absorption spectrum of HCO, were studied at 298 and 588 K, and the buffer gas (He) pressure of 1 bar. Pulsed laser photolysis (308, 320, and 193 nm) of acetaldehyde, propionaldehyde, and acetone was used to prepare mixtures of free radicals. The second-order rate constant of reaction (1) obtained from the data at 1 bar is: k 1 (He) = (0.8 ± 0.4) · 10 À10 exp(À(66.0 ± 3.4) kJ mol À1 /RT) cm 3 molecule À1 s À1 . The HCO dissociation rate constants measured in this work are lower than those reported in the previous direct work. The difference is a factor of 2.2 at the highest temperature of the experiments and a factor of 3.5 at the low end. The experimental data indicate pressure dependence of the rate constant of dissociation of formyl radical 1, which was attributed to the early pressure fall-off expected based on the theory of isolated resonances. The UV absorption spectrum of HCO was revised. The maximum absorption cross-section of HCO is (7.3 ± 1.2) · 10 À18 cm 2 molecule À1 at 230 nm (temperature independent within the experimental error). The measured rate constants for reactions and are: k 2 = (3.6 ± 0.8) · 10 À11 cm 3 molecule À1 s À1 (298 K); k 3 = (9.3 ± 2.3) · 10 À11 cm 3 molecule À1 s À1 (298 and 588 K).
A symposium. The dissocn. of formyl to CO and H was directly studied over an extended buffer gas ... more A symposium. The dissocn. of formyl to CO and H was directly studied over an extended buffer gas pressure range (1-100 bar). The results of the current measurements are in discrepancy of factor ∼2-3 with the previous data. Pressure dependence of the rate const. of this reaction was also obsd. [on SciFinder(R)]
The kinetics and mechanism of the title chlorination was studied by mass spectroscopy and discuss... more The kinetics and mechanism of the title chlorination was studied by mass spectroscopy and discussed in relation to the authors previous work using IR chemiluminescence and laser magnetic resonance. [on SciFinder(R)]
A new exptl. technique has been developed for direct time-resolved studies of the kinetics of aer... more A new exptl. technique has been developed for direct time-resolved studies of the kinetics of aerosol formation. It is based on a combination of pulsed excimer laser photolysis and space- and time-resolved monitoring of scattered light with a gated intensified CCD camera. The exptl. setup allowed detection of aerosol particles more than 45-50 nm in diam. and with the no. concn. ranging from 3 · 106 to 6 · 108 particles/cm3. The time range of aerosol formation kinetics was from 10-7 to 10-2 s. Kinetics of photochem. induced aerosol formation in 1,4-cyclohexadiene-NO-air mixt. was studied. The evolution of the particle no. concn. and the size distribution was investigated, as well as the increase in the scattered light intensity depending on a delay after the photolyzing pulse. Quantum yield of aerosol products was estd. to be in the range from 10-2 to 2%, which is comparable with the values characteristic of org. aerosols. [on SciFinder(R)]
Laser magnetic spectrometer (CO2 laser) with resonance modulation of magnetic field on frequency ... more Laser magnetic spectrometer (CO2 laser) with resonance modulation of magnetic field on frequency 150 kHz was used for study of decay kinetics of Cl and SiH3 radicals produced in pulse photolysis (4 harmonics of Nd laser) of S2Cl2/SiH4 system. The method time resoln. was 4μs, and its sensitivity with respect to Cl concn. recording 4 × 1010 cm3, and for SiH3 radicals (8 - 12) × 1010 cm3. The rates of Cl + SiH4 and SiH3 + S2Cl2 reactions were detd. as (2.3 ± 0.5) × 10-10 and (2.7 ± 0.5) × 10-11 cm3/s, resp. [on SciFinder(R)]
This work investigates the effects of attenuation on amplitude characteristics of P and S waves i... more This work investigates the effects of attenuation on amplitude characteristics of P and S waves in vertically transverse isotropic (VTI) media by constructing radiation patterns. Radiation pattern allows us to observe the focusing of energy in anisotropic attenuating media. Attenuation is incorporated in a medium by the quality factor (Q). The quality factor is defined as the quantity proportional to the ratio of the real and imaginary part of elastic coefficients. The quality factor essentially represents a viscoelastic medium. Low values of Q suggest a high attenuating medium and vice-versa. In general Q can be anisotropic; however, we have assigned same values of Q to P and S waves in order to investigate amplitude attenuation with respect to Q. Radiation patterns are constructed as a polar diagram by taking the maximum amplitude of the first motions of P- and S-waves in a given plane (vertical plane in our case). The radiation pattern can also be thought of as a far- field radia...
The sensitivity of the hydrocarbon combustion parameters such as the flame propagation speed, the... more The sensitivity of the hydrocarbon combustion parameters such as the flame propagation speed, the ignition delay, etc.) to the rate consts. of several elementary reactions of formyl radical (HCO) has been analyzed. Two major mechanisms, characteristic for lean and reach mixts., that have opposite impacts on the combustion parameters, were revealed. Several elementary reactions of formyl radical of combustion importance were studied using laser photolysis coupled to sensitive UV-Vis absorption spectroscopy: HCO H + CO (1), HCO + HCO products (2), HCO + CH3 products (3). Reaction 1 was studied over the buffer gas (He) pressure range 0.8 - 100 bar and the temp. range 498 - 769 K. Reactions 2 and 3, as well as the UV absorption spectrum of HCO, were studied at 298 K and 591 K, and the buffer gas (He) pressure of 1 bar. New rate consts. were obtained. The impact on the combustion modeling is discussed. [on SciFinder(R)]
A novel exptl. technique to study the kinetics of aerosol particles formation was developed. The ... more A novel exptl. technique to study the kinetics of aerosol particles formation was developed. The approach is based on the pulsed formation of an aerosol precursor with the subsequent time and particle resolved monitoring of the aerosol particle growth via the pulsed laser light scattering combined with the time-resolved imaging. The kinetics of the aerosol formation in the photolysis of mixts. of org. moleculs (cyclohexadiene, cyclohexene, toluene or chlorobenzene), nitric oxide, mol. oxygen and nitrogen were studied at ambient pressure and temp. The conversion of the scattered light intensity to the particle diam. was based on the calibration using spherical latex particles. The time evolutions of the particle size distribution functions were obtained. The exptl. results were compared with the model calcns. Several models for the aerosol particle formation under the pulsed initiation conditions were developed and numerically evaluated. [on SciFinder(R)]
A complete elementary reaction model of particle nucleation and growth from supersatd. solns. was... more A complete elementary reaction model of particle nucleation and growth from supersatd. solns. was developed and evaluated. The model includes all possible forward reactions (i.e., of monomers, dimers, trimers, etc.) together with thermodynamically consistent reverse processes. The kinetic model was numerically evaluated using the surface tension approxn. for the particle thermodn. The time evolution of the size distribution function was obtained. The results were compared with the predictions of the classical nucleation theory. The impact of the basic assumptions of the classical nucleation theory was assessed, and the applicability limits of the theory were outlined. Model calcns. were performed for nano-particle formation by Rapid Expansion of Supercrit. Solns. (RESS) and compared with the exptl. observations. [on SciFinder(R)]
Better understanding of combustion phenomena requires advanced combustion models which incorporat... more Better understanding of combustion phenomena requires advanced combustion models which incorporate detailed chemical kinetics mechanisms. Combustion efficiency and stability, internal engine knock, emission of environmentally noxious substances are the problems which require detailed chemical kinetics mechanisms with well characterized elementary reactions over extended temperature and pressure ranges. Reaction conditions with high and variable pressures are encountered in practically important combustion processes, e.g., in internal combustion engines. Laboratory measurements are usually performed at "convenient" pressures (0.001 - 1 bar), extrapolations to higher pressures are based on theoretical foundations and introduce significant additional uncertainties into the model predictions. Buffer gas density affects the rates and branching ratios of dissociation and isomerization reaction, bimolecular reactions that proceed via an intermediate complex, as well as the corres...
extended (0.01 - 100 bar, 298 – 834 K for OH+OH, 1-100 bar, 298 – 715 K for CH3+OH and CH3+CH3)... more extended (0.01 - 100 bar, 298 – 834 K for OH+OH, 1-100 bar, 298 – 715 K for CH3+OH and CH3+CH3) pressure and temperature ranges by pulsed excimer laser photolysis coupled with transient absorption spectroscopy was completed. Acetone was used as a photochemical precursor of CH3 radicals at 193 nm, photolysis of N2O/H2O was used to produce OH radicals at 193 nm (via the fast reaction O(1D) + H2O). Methyl and hydroxyl radicals were monitored by transient absorption at 215 nm and 308 nm, respectively. In the reaction of methyl radicals with hydroxyl radicals CH3 + OH 1CH2 + H2 O (1a) CH3OH (1b) other products (1c) no pressure dependence was found over the pressure range 1 – 100 bar at all temperatures, indicating negligible contribution of the pressure dependent stabilization channel 1b. These measurements fill the gap between the near ambient temperature and high temperature shock tube studies of reaction 1.1,2 In the self-reaction of hydroxyl radical OH + OH H2O + O (2a) ...
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Papers by Evgeni Chesnokov